Technologists and the consuming public have held a fascination with three-dimensional viewing systems essentially since the advent of practical photography. Early scenes were viewed through parallax-based stereopticon or magic lantern devices. In time, the image dynamics of cinematography appeared, leading to parallax-based three-dimensional imaging in that field which was viewed with dual-colored or polarized lens based eyewear. More currently, stereo vision has been offered in conjunction with liquid crystal shutter containing goggles and in connection with the helmets employed with virtual reality-based systems.
Complex but precise three-dimensional systems evolved with that brand of interferometry known as holography and the emergence of holographic film in conjunction with the practical laser. Advancing technology also turned to what has been termed "real time" holography where a spatial light modulator is electronically driven to achieve an electronic reconstruction display of a three-dimensional holographic image. Through resort to highly miniaturized grid matrix technology, the fringe pattern itself is constructed electro-optically. Such technology is, for example, described in U.S. Pat. No. 4,494,219 by Kirk, entitled "Electrically Generated Holography", issued Nov. 20, 1984. Improvements to the spatial modulator component of this technology are described in U.S. Pat. No. 4,566,031 by Kirk, entitled "Spatial Light Modulation with Application to Electrically Generated Holography", issued Jan. 21, 1986. Technology addressed to reducing the complexity of holographic based stereoscopic imaging looked, for example, to the utilization of a cathode ray tube carrying real images of the scene or images generated with computer graphics in conjunction with a holographic integrating combiner screen. Such combiner screens function to form a number of fringe-pattern defined optical components having a corresponding number of spaced-apart back focal planes or points, each of which transmits an image sample from a synthetic aperture to a forward focal point. The output positions are spaced mutually laterally to achieve a binocular perspective viewing at a zone located at one or more viewing stations. These systems are described by Kirk in U.S. Pat. No. 5,379,133, issued Jan. 3, 1995, entitled "Synthetic Aperture-Based Real Time Holographic Imaging".
More recently, interest has developed in the generation of relatively inexpensive images in free space. Such systems have application, for example, in connection with advertising at points of sale or in developing corporate images or for forming free space images for trade shows and the like. Other utilization for such imaging is in museums or more casual environments where the casual observer is not called upon to use eyewear or any such implements. However, the free space type of image represents an attractive or entertaining feature. To the present, the systems evolved have taken advantage of the large apertures available with Fresnel forms of lenses but have exhibited severely limited fields of view for the observer, substantial light scattering problems, and a lack of appreciable three-dimensional attributes.